Platform trailers are used to transport a variety of cargo that can withstand exposure to the weather or a wide range of road conditions. These trailers can be classified into three categories: “lowboy” (also known as “gooseneck”), “flatbed,” and “drop deck” trailers.
Lowboy trailers, as the term implies, have low “beds” or “decks,” situated close to the road so they can carry tall items that must clear bridges, power lines, and other over head obstacles, while providing a low center of gravity to enhance stability of large loads. Typically a lowboy trailer has a deck that can be detached from the assembly that connects it to the fifth wheel of a road tractor, commonly referred to as a “gooseneck,” to facilitate the loading of heavy items such as a piece of construction equipment. A flatbed trailer has a deck that extends the entire length of the trailer and is situated just above the wheels of the tractor and the trailer's wheel assemblies. Its standardized deck height provides good road clearance, and the flatbed trailer is designed to accept cargo, such as a shipping container, from a loading dock with little or no lifting. The drop deck trailer is less common than the other two types. Its deck is above that of a lowboy trailer yet below that of a flatbed trailer and is typically designed to carry specific items.
There is a need to have a single trailer that can be easily configured as a lowboy, flatbed, or drop deck trailer to accommodate any cargo the trailer may be required to carry. To some extent, this need has been recognized in the art. For example, see U.S. Pat. Nos. 2,676,783, 4,806,065, 5,059,083, 6,425,627. However, the trailers of the art typically allow for configuration only as lowboy or flatbed trailers, but not as drop deck trailers for which a need still exists. Further, the trailers of the art are complicated and time consuming to reconfigure, and in some cases are less stable than fixed deck trailers.